/* Copyright (C) 1993, 1994, 1995, 1996, 1997 Free Software Foundation, Inc. Contributed by Paul Eggert (eggert@twinsun.com). NOTE: The canonical source of this file is maintained with the GNU C Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *//* Define this to have a standalone program to test this implementation of mktime. *//* #define DEBUG 1 */#ifdef HAVE_CONFIG_H# include <config.h>#endif/* Some hosts need this in order to declare localtime_r properly. */#ifndef _REENTRANT# define _REENTRANT 1#endif#ifdef _LIBC# define HAVE_LIMITS_H 1# define HAVE_LOCALTIME_R 1# define STDC_HEADERS 1#endif/* Assume that leap seconds are possible, unless told otherwise. If the host has a `zic' command with a `-L leapsecondfilename' option, then it supports leap seconds; otherwise it probably doesn't. */#ifndef LEAP_SECONDS_POSSIBLE# define LEAP_SECONDS_POSSIBLE 1#endif#include <sys/types.h> /* Some systems define `time_t' here. */#include <time.h>#if HAVE_LIMITS_H# include <limits.h>#endif#if DEBUG# include <stdio.h># if STDC_HEADERS# include <stdlib.h># endif/* Make it work even if the system's libc has its own mktime routine. */# define mktime my_mktime#endif /* DEBUG */#ifndef __P# if defined (__GNUC__) || (defined (__STDC__) && __STDC__)# define __P(args) args# else# define __P(args) ()# endif /* GCC. */#endif /* Not __P. */#ifndef CHAR_BIT# define CHAR_BIT 8#endif#ifndef INT_MIN# define INT_MIN (~0 << (sizeof (int) * CHAR_BIT - 1))#endif#ifndef INT_MAX# define INT_MAX (~0 - INT_MIN)#endif#ifndef TIME_T_MIN/* The outer cast to time_t works around a bug in Cray C 5.0.3.0. */# define TIME_T_MIN ((time_t) \ (0 < (time_t) -1 ? (time_t) 0 \ : ~ (time_t) 0 << (sizeof (time_t) * CHAR_BIT - 1)))#endif#ifndef TIME_T_MAX# define TIME_T_MAX (~ (time_t) 0 - TIME_T_MIN)#endif#define TM_YEAR_BASE 1900#define EPOCH_YEAR 1970#ifndef __isleap/* Nonzero if YEAR is a leap year (every 4 years, except every 100th isn't, and every 400th is). */# define __isleap(year) \ ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))#endif/* How many days come before each month (0-12). */constunsignedshortint__mon_yday[2][13]={/* Normal years. */{0,31,59,90,120,151,181,212,243,273,304,334,365},/* Leap years. */{0,31,60,91,121,152,182,213,244,274,305,335,366}};staticstructtm*ranged_convert__P((structtm*(*)__P((consttime_t*,structtm*)),time_t*,structtm*));statictime_tydhms_tm_diff__P((int,int,int,int,int,conststructtm*));time_t__mktime_internal__P((structtm*,structtm*(*)(consttime_t*,structtm*),time_t*));#ifdef _LIBC# define localtime_r __localtime_r#else# if ! HAVE_LOCALTIME_R && ! defined localtime_r/* Approximate localtime_r as best we can in its absence. */# define localtime_r my_mktime_localtime_rstaticstructtm*localtime_r__P((consttime_t*,structtm*));staticstructtm*localtime_r(t,tp)consttime_t*t;structtm*tp;{structtm*l=localtime(t);if(!l)return0;*tp=*l;returntp;}# endif /* ! HAVE_LOCALTIME_R && ! defined (localtime_r) */#endif /* ! _LIBC *//* Yield the difference between (YEAR-YDAY HOUR:MIN:SEC) and (*TP), measured in seconds, ignoring leap seconds. YEAR uses the same numbering as TM->tm_year. All values are in range, except possibly YEAR. If TP is null, return a nonzero value. If overflow occurs, yield the low order bits of the correct answer. */statictime_tydhms_tm_diff(year,yday,hour,min,sec,tp)intyear,yday,hour,min,sec;conststructtm*tp;{if(!tp)return1;else{/* Compute intervening leap days correctly even if year is negative. Take care to avoid int overflow. time_t overflow is OK, since only the low order bits of the correct time_t answer are needed. Don't convert to time_t until after all divisions are done, since time_t might be unsigned. */inta4=(year>>2)+(TM_YEAR_BASE>>2)-!(year&3);intb4=(tp->tm_year>>2)+(TM_YEAR_BASE>>2)-!(tp->tm_year&3);inta100=a4/25-(a4%25<0);intb100=b4/25-(b4%25<0);inta400=a100>>2;intb400=b100>>2;intintervening_leap_days=(a4-b4)-(a100-b100)+(a400-b400);time_tyears=year-(time_t)tp->tm_year;time_tdays=(365*years+intervening_leap_days+(yday-tp->tm_yday));return(60*(60*(24*days+(hour-tp->tm_hour))+(min-tp->tm_min))+(sec-tp->tm_sec));}}statictime_tlocaltime_offset;/* Convert *TP to a time_t value. */time_tmktime(tp)structtm*tp;{#ifdef _LIBC/* POSIX.1 8.1.1 requires that whenever mktime() is called, the time zone names contained in the external variable `tzname' shall be set as if the tzset() function had been called. */__tzset();#endifreturn__mktime_internal(tp,localtime_r,&localtime_offset);}/* Use CONVERT to convert *T to a broken down time in *TP. If *T is out of range for conversion, adjust it so that it is the nearest in-range value and then convert that. */staticstructtm*ranged_convert(convert,t,tp)structtm*(*convert)__P((consttime_t*,structtm*));time_t*t;structtm*tp;{structtm*r;if(!(r=(*convert)(t,tp))&&*t){time_tbad=*t;time_tok=0;structtmtm;/* BAD is a known unconvertible time_t, and OK is a known good one. Use binary search to narrow the range between BAD and OK until they differ by 1. */while(bad!=ok+(bad<0?-1:1)){time_tmid=*t=(bad<0?bad+((ok-bad)>>1):ok+((bad-ok)>>1));if((r=(*convert)(t,tp))){tm=*r;ok=mid;}elsebad=mid;}if(!r&&ok){/* The last conversion attempt failed; revert to the most recent successful attempt. */*t=ok;*tp=tm;r=tp;}}returnr;}/* Convert *TP to a time_t value, inverting the monotonic and mostly-unit-linear conversion function CONVERT. Use *OFFSET to keep track of a guess at the offset of the result, compared to what the result would be for UTC without leap seconds. If *OFFSET's guess is correct, only one CONVERT call is needed. */time_t__mktime_internal(tp,convert,offset)structtm*tp;structtm*(*convert)__P((consttime_t*,structtm*));time_t*offset;{time_tt,dt,t0;structtmtm;/* The maximum number of probes (calls to CONVERT) should be enough to handle any combinations of time zone rule changes, solar time, and leap seconds. POSIX.1 prohibits leap seconds, but some hosts have them anyway. */intremaining_probes=4;/* Time requested. Copy it in case CONVERT modifies *TP; this can occur if TP is localtime's returned value and CONVERT is localtime. */intsec=tp->tm_sec;intmin=tp->tm_min;inthour=tp->tm_hour;intmday=tp->tm_mday;intmon=tp->tm_mon;intyear_requested=tp->tm_year;intisdst=tp->tm_isdst;/* Ensure that mon is in range, and set year accordingly. */intmon_remainder=mon%12;intnegative_mon_remainder=mon_remainder<0;intmon_years=mon/12-negative_mon_remainder;intyear=year_requested+mon_years;/* The other values need not be in range: the remaining code handles minor overflows correctly, assuming int and time_t arithmetic wraps around. Major overflows are caught at the end. *//* Calculate day of year from year, month, and day of month. The result need not be in range. */intyday=((__mon_yday[__isleap(year+TM_YEAR_BASE)][mon_remainder+12*negative_mon_remainder])+mday-1);intsec_requested=sec;#if LEAP_SECONDS_POSSIBLE/* Handle out-of-range seconds specially, since ydhms_tm_diff assumes every minute has 60 seconds. */if(sec<0)sec=0;if(59<sec)sec=59;#endif/* Invert CONVERT by probing. First assume the same offset as last time. Then repeatedly use the error to improve the guess. */tm.tm_year=EPOCH_YEAR-TM_YEAR_BASE;tm.tm_yday=tm.tm_hour=tm.tm_min=tm.tm_sec=0;t0=ydhms_tm_diff(year,yday,hour,min,sec,&tm);for(t=t0+*offset;(dt=ydhms_tm_diff(year,yday,hour,min,sec,ranged_convert(convert,&t,&tm)));t+=dt)if(--remaining_probes==0)return-1;/* Check whether tm.tm_isdst has the requested value, if any. */if(0<=isdst&&0<=tm.tm_isdst){intdst_diff=(isdst!=0)-(tm.tm_isdst!=0);if(dst_diff){/* Move two hours in the direction indicated by the disagreement, probe some more, and switch to a new time if found. The largest known fallback due to daylight savings is two hours: once, in Newfoundland, 1988-10-30 02:00 -> 00:00. */time_tot=t-2*60*60*dst_diff;while(--remaining_probes!=0){structtmotm;if(!(dt=ydhms_tm_diff(year,yday,hour,min,sec,ranged_convert(convert,&ot,&otm)))){t=ot;tm=otm;break;}if((ot+=dt)==t)break;/* Avoid a redundant probe. */}}}*offset=t-t0;#if LEAP_SECONDS_POSSIBLEif(sec_requested!=tm.tm_sec){/* Adjust time to reflect the tm_sec requested, not the normalized value. Also, repair any damage from a false match due to a leap second. */t+=sec_requested-sec+(sec==0&&tm.tm_sec==60);if(!(*convert)(&t,&tm))return-1;}#endifif(TIME_T_MAX/INT_MAX/366/24/60/60<3){/* time_t isn't large enough to rule out overflows in ydhms_tm_diff, so check for major overflows. A gross check suffices, since if t has overflowed, it is off by a multiple of TIME_T_MAX - TIME_T_MIN + 1. So ignore any component of the difference that is bounded by a small value. */doubledyear=(double)year_requested+mon_years-tm.tm_year;doubledday=366*dyear+mday;doubledsec=60*(60*(24*dday+hour)+min)+sec_requested;if(TIME_T_MAX/3-TIME_T_MIN/3<(dsec<0?-dsec:dsec))return-1;}*tp=tm;returnt;}#ifdef weak_aliasweak_alias(mktime,timelocal)#endif#if DEBUGstaticintnot_equal_tm(a,b)structtm*a;structtm*b;{return((a->tm_sec^b->tm_sec)|(a->tm_min^b->tm_min)|(a->tm_hour^b->tm_hour)|(a->tm_mday^b->tm_mday)|(a->tm_mon^b->tm_mon)|(a->tm_year^b->tm_year)|(a->tm_mday^b->tm_mday)|(a->tm_yday^b->tm_yday)|(a->tm_isdst^b->tm_isdst));}staticvoidprint_tm(tp)structtm*tp;{if(tp)printf("%04d-%02d-%02d %02d:%02d:%02d yday %03d wday %d isdst %d",tp->tm_year+TM_YEAR_BASE,tp->tm_mon+1,tp->tm_mday,tp->tm_hour,tp->tm_min,tp->tm_sec,tp->tm_yday,tp->tm_wday,tp->tm_isdst);elseprintf("0");}staticintcheck_result(tk,tmk,tl,lt)time_ttk;structtmtmk;time_ttl;structtm*lt;{if(tk!=tl||!lt||not_equal_tm(&tmk,lt)){printf("mktime (");print_tm(&tmk);printf(")\nyields (");print_tm(lt);printf(") == %ld, should be %ld\n",(long)tl,(long)tk);return1;}return0;}intmain(argc,argv)intargc;char**argv;{intstatus=0;structtmtm,tmk,tml;structtm*lt;time_ttk,tl;chartrailer;if((argc==3||argc==4)&&(sscanf(argv[1],"%d-%d-%d%c",&tm.tm_year,&tm.tm_mon,&tm.tm_mday,&trailer)==3)&&(sscanf(argv[2],"%d:%d:%d%c",&tm.tm_hour,&tm.tm_min,&tm.tm_sec,&trailer)==3)){tm.tm_year-=TM_YEAR_BASE;tm.tm_mon--;tm.tm_isdst=argc==3?-1:atoi(argv[3]);tmk=tm;tl=mktime(&tmk);lt=localtime(&tl);if(lt){tml=*lt;lt=&tml;}printf("mktime returns %ld == ",(long)tl);print_tm(&tmk);printf("\n");status=check_result(tl,tmk,tl,lt);}elseif(argc==4||(argc==5&&strcmp(argv[4],"-")==0)){time_tfrom=atol(argv[1]);time_tby=atol(argv[2]);time_tto=atol(argv[3]);if(argc==4)for(tl=from;tl<=to;tl+=by){lt=localtime(&tl);if(lt){tmk=tml=*lt;tk=mktime(&tmk);status|=check_result(tk,tmk,tl,tml);}else{printf("localtime (%ld) yields 0\n",(long)tl);status=1;}}elsefor(tl=from;tl<=to;tl+=by){/* Null benchmark. */lt=localtime(&tl);if(lt){tmk=tml=*lt;tk=tl;status|=check_result(tk,tmk,tl,tml);}else{printf("localtime (%ld) yields 0\n",(long)tl);status=1;}}}elseprintf("Usage:\\t%s YYYY-MM-DD HH:MM:SS [ISDST] # Test given time.\n\\t%s FROM BY TO # Test values FROM, FROM+BY, ..., TO.\n\\t%s FROM BY TO - # Do not test those values (for benchmark).\n",argv[0],argv[0],argv[0]);returnstatus;}#endif /* DEBUG *//*Local Variables:compile-command: "gcc -DDEBUG -D__EXTENSIONS__ -DHAVE_LIMITS_H -DHAVE_LOCALTIME_R -DSTDC_HEADERS -Wall -W -O -g mktime.c -o mktime"End:*/